In the dim light of a cinema auditorium it is reassuring to have the bright beam of an usher's torch as a reliable guide. Today the Observer can announce the identity of the new film critic who will be steering our readers towards the screen from next month.

Mark Kermode, a man with an instantly recognisable passion for cinema and a fearlessly independent voice, is to become chief film critic following the retirement of Philip French. Kermode, a long-time admirer of French's film writing, works in BBC radio and on television, as well as writing for Sight and Sound and reviewing DVD releases for this newspaper, and is the author of several acclaimed books on film.

"I'm honoured and thrilled to be taking over as film critic for the Observer," said Kermode. "The paper is second to none, and writing for it has always been a privilege and a joy. When I first started working as a film critic over 25 years ago, Philip's Observer reviews were an inspiration. No one can match his breadth of knowledge or elegance of expression, but I hope I can bring to the role the passion for cinema which Observer readers expect."

Kermode, who grew up in East Finchley, north London, began his reviewing career as a PhD student in Manchester and then worked in London on the weekly magazines Time Out and New Musical Express. He remembers spotting French at those early press screenings. "I remember the strange feeling, sitting near my heroes, thinking, 'I am at the big table now.' I believe, as Philip does, that there is still a place for a professional critic and I am fiercely proud to be one."

Film, Kermode said, has been the "single overwhelming obsession of my life", although he came to it, as followers of his criticism will know, through a love of horror. "Those films were my first love, but of course I feel you have to be open-minded to all genres of films. People always tell you that you will grow out of horror movies. Well, I am 50 now and there is no sign of that happening."

In the same way that French retains his appetite for the western genre, Kermode makes no apologies for blood and gore. "Philip knows westerns inside out, but there was no sense that it ever stopped him understanding everything else that was going on in film. He was very even-handed, with a wonderful writing style. It goes without saying it is a very hard act to follow."

If Kermode has a mission it will be to recreate the excitement he felt as a teenager visiting Britain's repertory venues, desperate to see another David Cronenberg or David Lynch. "Those cinemas offered you a programme. Somewhere like the old Scala in King's Cross would show a range of things, from Laurel and Hardy to Buñuel to modern horror. This was before video and DVD, so for me going to the cinema was the big thing."

The job of the critic is on Kermode's mind more than usual this weekend as he finishes his latest book, Hatchet Job: Love Movies, Hate Critics. "Film criticism has always been the home of the well-turned and pithy put-down, because in the end it is all personal," he said.

For Kermode, a critic should first "accurately describe a film and then ascribe it to the right school of film, before mentioning its tangential connections to other films. Beyond that, your opinion is opinion and my feeling is that you should be honest about that. I don't think the reader has to agree with you and I don't think a critic is there to tell you what to see. They are there to contextualise, to describe, to be passionately honest and entertaining."

French will write his last column for the Observer on 1 September, after 50 years in the job. On his resignation, he said he believed cinema was the great art form of the last century and that this century was continuing the same way. So, as the credits finally roll on the French era at the Observer, readers can now take their seats in the auditorium, ready, not for a sequel, but for a new, impassioned critical standpoint.

As Kermode recalls: "Philip said to me recently: 'For people in our line of work, the Observer is the best chair in the world'. As always, he is absolutely right."